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Amhras
09-13-2007, 11:19 AM
I'm going a little nuts with getting a good looking, high impact explosion using HV. The explosions are for a still shot, but to get the motion blur to come out I've got everything animated to one extent or another. Does anyone know of a good Tut for doing photo-real HV explosions? I keep winding up with blobs of smoke that just look downright wrong. I do have Dynamite Lite, but the rendertime on that is just unacceptable (as it is, the shot is taking in excess of 24 hours at 35 pass aa)

SplineGod
09-13-2007, 12:25 PM
Can you post what you have so far?

Amhras
09-13-2007, 12:41 PM
This is the image as it currently stands.

stevecullum
09-14-2007, 05:00 AM
Looking at my reference image, I would say you have way too much motion blur going on their. What are you using for reference?

I would be inclined to use a combo of HV's and real explosion photos to get the exact look you after - nothing like the real thing for a photo real look!

starbase1
09-14-2007, 10:05 AM
This is the image as it currently stands.

I think your HV's look a bit sharp edged - I've never managed to get rid of a clearly defined edge look on my HV's - a real shame as I like the idea of sculpting in soft smoke and mist!

stevecullum
09-14-2007, 10:55 AM
I think your HV's look a bit sharp edged - I've never managed to get rid of a clearly defined edge look on my HV's

I think one of Mr Rid's top HV tips was to scale up 100% to soften the edges. Also helps with render times :)

starbase1
09-15-2007, 07:30 AM
I think one of Mr Rid's top HV tips was to scale up 100% to soften the edges. Also helps with render times :)

Now this I really do not understand... Surely 100% is the same size? And are we talking the texture, the HV's or what?!?!

Can you point me at the thread you mean please?

Thanks,
Nick

stevecullum
09-15-2007, 08:07 AM
I mean 200%!

The thread of interest is here:

http://www.newtek.com/forums/showthread.php?t=70370&highlight=Rid

I'm sure somewhere in that discussion its mentioned that you can render at 50% and scale up or I think another one to reduce render times was to render every other frame and frame blend them in post.

Its an insightful read :)

edit: here's the section...


For instance, I have never rendered smoke above 640x for a feature film effect. HV actually looks worse with the higher it's rez and has to be softened anyway. Save the render time and upscale from 640x and let the scale dithering soften it for you. The hazy smoke in the 'Fireball' example was actually rendered at 360x.

Amhras
09-18-2007, 12:44 PM
Thanks for the link! I want a fair amount of motion blur to give that nice feeling of high impact, as if the explosives casing them have just gone off. The hard edging is definitely a problem, as is my lack of debris.

SplineGod
09-18-2007, 12:49 PM
I would separate things down into various parts.
The debris created by the impact and explosion.
You also have an initial bright flash.
Then you have the fireball which gets darker as it
starts to cool and moves upward as well as a smoke
trail following the fireball.

Anti-Distinctly
09-25-2007, 01:36 AM
I do explosions as follows:
Use an emitter setup similar to the recent Siggraph video posted by Newtek. It's basically one initial emitter to send out a few particles with a relatively high 'explosion' parameter.
Then parent another emitter to that to leave trails behind.
Add some wind (I use doughnut) to get some turbulence style effect.
Add some relative particle age gradients to the colour and luminosity and you should be just about there. Just choose an appropriate frame that looks best for you.

Sande
09-26-2007, 02:44 AM
Amhras, your explosion, even if it's not very realistic, doesn't look too bad as it is - it looks a bit like stylized artsyfartsy comic explosion, in a good way. :)

Amhras
09-27-2007, 02:06 PM
Thank you all for the replies. I'm definitely going to have to comp the explosions to get the effect I want(I tried this with another shot that I'm attaching here). For the moment I have it in a state that is at least sufficient for what my client on this one wants. Gonna keep working on it till I'm happy, tho....